Circuit interrupter construction with improved condenser



Jan. 18, 1966 s. I. LINDELL 3,230,331

CIRCUIT INTERRUPTER CONSTRUCTION WITH IMPROVED CONDENSER Filed April 26, 1965 6 Sheets-Sheet 1 26 36 39 Z 42 m 56 1 .56 i5 541' 26 .26

Jan. 18, 1966 S. I. LlNDELL CIRCUIT INTERRUPTER CONSTRUCTION WITH IMPROVED CONDENSER Filed April 26, 1965 6 Sheets-Sheet 2 6 Sheets-Sheet 5 S. l. LINDELL CIRCUIT INTERRUPTER CONSTRUCTION WITH IMPROVED CONDENSER Jan. 18, 1966 Filed April 26, 1965 Jfl- S. l. LINDELL Jan. 18, 1966 CIRCUIT INTERRUPTER CONSTRUCTION WITH IMPROVED CONDENSER Filed April 26, 1965 6 Sheets-Sheet 4 Jan. 18, 1966 LINDELL 3,230,331

CIRCUIT INTERRUPTER CONSTRUCTION WITH IMPROVED CONDENSER Filed April 26, 1965 6 Sheets-Sheet 5 S. I. LINDELL Jan. 18, 1966 CIRCUIT INTERRUPTER CONSTRUCTION WITH IMPROVED CONDENSER Filed April 26, 1965 6 Sheets-Sheet 6 252 im Mir Z571 1 I United States Patent 3,230,331 CIRCUIT IIITERRUPTER CONSTRUCTION WITH IMPROVED CONDENSER Sigurd I. Lindell, Northbrook, I]l., assignor to .S & C Electric Company, Chicago, -Ill., a corporation of Delaware Filed Apr. 26, 1965, SerrNo. 450,748 Claims. (Cl. 200120) This application is a continuation-in-part of applications Serial No. 857,381, filed December 4 ,1959; Serial No. 200,766, filed June 7, 1962; and Serial No. 308,394, field September 12, 1963.

This invention relates, generally, to circuit interrupters for use on high voltage, high current electric transmission and distribution circuits and it has particular relation to the construction of means for reducing the external effects of blast action resulting from the operation of the interrupter. The present invention can be employed with various types of circuit interrupters .oneof which is illustrated in US. Patent No. 2,976,381, issued March 21, 1961, to applicant.

When fuses of the boric acid type, such as the type disclosed in the patent above referred to in which .a large quantity of water vapor is evolved-on high current-operation, are installed indoors or in metal enclosed switch gear assemblies, it is customary to employ a muffler or condenser at the exhaust end of the arc interrupting bore of the fuse in order to confine the are .core and to cool and condense vpart or all of the exhaust vapors for the purpose ofreducing or eliminating the amount of incandescent exhaust material that reaches the exterior of the fuse and also to reduce the shock wave that may accompany the operation of the device at high current levels. One type of condenser or mufiler that is used is of the nonvented .construction, such as shown in US. Patent No. 2,184,760, issued December 26, 1939, to J. M. Wallace, which permits installation in an enclosure of relatively light wall construction and minimum size fora given voltage and interrupting rating. Other types of fuses are designed to operate with condensers venting relatively freely to the outside to facilitate interrupting high fault currents, for example as shown in U.S. Patent No. 2,379,200, issued June 26, 1945, -to H. H. Triplett, with attendant shock waves of magnitudes requiring stronger, larger and more expensive enclosures.

Tests have shown that non-vented condensers of economically acceptable size and weight for a given voltage and interrupting rating .are deficient in some respects. They interfere with the flow of arc extinguishing vapors and other arc products from the interrupting bore of the fuse to such an extent that successful operation on high fault currents is not always achieved under severe conditions of recovery voltage. Under such operating conditions the arcing time is increased and likewise the total amount of energy generated and stored within the fuse assembly and condenser is increased. The energy and resultant temperatures and pressures become many times greater than in fuses employing relatively free venting condensers at the same short circuit current levels. When full rated voltage is maintained across fuses employing such non-vented condensers, immediately following and for some time after initial interruption of a high short circuit current (equal to or approaching the interrupting rating) the high temperature of the condenser produces a heat flow of considerable magnitude into the fuse unit with a consequent further temperature rise and particularly at the arcing end of the .fuse unit adjacent the condenser. This is accompanied by a reduction in dielectric strength which has been found by tests to promote restriking of the arc and sustained arcing in the interrupting 3,230,331 Patented Jan. 18, 1966 bore or in the airgap outside the refill unit or replaceable cartridge with ultimate explosive destruction of the entire fuse unit. This defeats the original purpose of the nonvented condenser.

One object of this invention is to provide a semi-vented condenser of substantially the same size, weight and cost as a non-Vented condenser for operation with a fuse of a given voltage and interrupting rating so constructed as to obviate the shortcomings mentioned above when the nonvented type of condenser is employed.

Another object of this invention is to so construct the condenser that the shock wave is greatly reduced in comparison with the shock Wave attending the operation of fuses equipped with vented condensers of the type above referred to so that condensers of the improved type embodying the present invention can be employed in enclosures of substantially the same relatively light compact construction as would be provided for housing fuses having no provision for venting them.

Still another object of this invention is to provide the combination of a fuse employing a solid arc extinguishing material, such as boric acid from which a large quantity of water vapor can be evolved, and a condenser at the exhaust or arcing end of the fuse having a relatively large diameter chamber formed by a condensing screen body for initially receiving the are blast, with the large diameter chamber in endwise coaxial relation to a relatively small diameter chamber formed by a condensing screen body arranged to disperse the products of the arc blast from the large diameter chamber into the screen body around the small diameter chamber and thence through vent openings to the atmosphere in such manner that there is no direct ,path for the flow of the products of the arc blast from the exhaust end of the fuse to the atmosphere.

Other objects of this invention are: to shield the screen body from direct attack by the arc vdrawn on blowing of the fusible element or the plasma blast from the interrupting bore; to accomplish this by interposing members of substantial cross section and/or heat capacity to provide a barrier between the interrupting bore and the screen in line therewith and to facilitate the transfer of one are root to such a member of metal in lieu of the screen body thereby reducing the vaporization of metal, such as copper, which must be cooled before it is permitted to reach the atmosphere; vto mount the barrier member at one end of a tubular member orstem whose opening extends through the barrier member and is in direct line with the interrupting bore to receive a limited portion of the discharge therefrom; to provide limited lateral openings through the wall of the tubular member which extends through the convolutely wound reticulated metal filling in the shell of the condenser or mufiler at points spaced from its discharge end to permit the flow of arc products from the tubular member into the metal filling; to facilitatecentering the arc and the .plasma blast from the interrupting bore to prevent direct impingement thereof on the screen body while the major part of the discharge is deflected into the screen body; to format least a part of the barrier member'of arc resisting material, such as a ceramic material or are resisting metal such as silver tungsten or tungsten carbide; to position the barrier member normally adjacent the discharge end of the interrupting bore and to provide for mounting it for limited movement away from such discharge end under the influence of the arc blast; to mount the barrier memher on one end of a stem that is movable through the tubular member extending through the reticulated metal filling with a spring acting on the other end to bias the barrier member to its normal position adjacent the discharge end of the interrupting bore; to provide the movable stem with a longitudinally extending aperture communicating with apertures in the tubular member to direct a part of the arc products into the surrounding metal fillings; to cause the are products to flow from the reticulated metal filling through an apertured annular disc into an exhaust chamber in the condenser or muffler the opposite side of which is formed by a second apertured annular disc which constitutes the closure for the condenser or mufiier housing, the openings through the two discs being laterally displaced to the end that the flow of the are products through the exhaust chamber is turbulent and indirect rather than direct; and to provide a relatively limited total vent area in the form of relatively small openings in the first annular disc to restrict the flow of the are products and a relatively large total vent area in the form of relatively large openings in the second annular disc to permit relatively free flow of the are products from the exhaust chamber to the atmosphere and to reduce the velocity and reach of the exhaust jets.

Additional objects of this invention are: To position an imperforate deflecting member in the direct path of the blast of arc products for distributing them among the interstices of the screen body; to provide for this purpose a metallic stud having an imperforate head to be impinged directly by the arc blast and a body that extends into and completely fills the central longitudinal space through the convolutely wound screen body, the head deflecting the are products laterally into the surrounding convolutely wound screen body that defines a space having a greater cross sectional area than the area of the discharge passageway; and to extend the screen body that surrounds the stud fully to the ported closure at the outer end of the cylindrical shell in which the screen body is located with the stud being secured to this closure centrally thereof.

Other objects of this invention will, in part, be obvious and in part appear hereinafter.

This invention is disclosed in the embodiments thereof shown in the accompanying drawings and it comprises the features of construction, combination of elements and arrangement of parts that will be exemplified in the construction hereinafter set forth and the scope of the application of which will be indicated in the appended claims.

For a more complete understanding of the nature and scope of this invention, reference can be had to the following detailed description, taken together with the accompanying drawings, in which:

FIG. 1 is a perspective view of a circuit interrupter in which the present invention is embodied;

FIGS. 2A and 2B, taken together with the former placed above the latter, show a vertical longitudinal sectional view through the circuit interrupter illustrated in FIG. 1 and through a portion of the condenser therefor, the remaining portion of the condenser being shown in elevation;

FIG. 3 is a vertical sectional view, at an enlarged scale, showing the details of construction of the condenser or muffler shown in FIG. 2B;

FIG. 4 is a bottom plan view of the condenser shown in FIG. 3;

FIG. 5 is a horizontal sectional view taken generally FIG. 6 is a view, in side elevation, of the short section FIG. 6 is a view, in side elevation, of thet short section of convolutely wound rigid wire screen that is employed in the shell of the condenser for initially receiving and cooling the exhaust gas from the circuit interrupter;

FIG. 7 is a view, similar to FIG. 3, showing a modified construction;

FIG. 8 is a horizontal sectional view taken along the line 88 of FIG. 7;

FIG. 9 is a bottom plan view of FIG. 7;

FIG. 10 is a View, similar to FIG. 2B, and illustrates a modified condenser or muffler construction;

FIG. 11 is a horizontal sectional view taken generally along the line 1111 of FIG. 10.

FIG. 12 is a horizontal sectional view taken generally along the line 12-12 of FIG. 10;

FIG. 13 is a vertical sectional view at an enlarged scale, showing a modified form of the barrier member shown in FIG. 10;

FIG. 14 is a view in vertical section of a further modification of the condenser or muffler which can be employed in lieu of the condensers or mufilers shown in FIGS. 28, 7 and 10;

FIG. 15 is a horizontal sectional view taken generally along the line 1515 of FIG. 14;

FIG. 16 is a horizontal sectional view taken generally along the line 1616 of FIG. 14 and showing another modification;

FIG. 17 is a vertical sectional view that shows another form of the condenser or muflier which can be used with the fuse construction illustrated in FIGS. 2A-2B;

FIG. 18 is a bottom plan view of the condenser or mufiler shown in FIG. 17;

FIG. 19 is a view, similar to FIG. 17,. and shows certain modifications of the details of construction;

FIG. 20 is a view, similar to FIGS. 17 and 19; and shows additional details of construction of a somewhat different nature;

FIG. 21 is a horizontal sectional view taken generally along the line 21-21 of FIG. 20; and

FIG. 22 shows a modified mounting arrangement for the stud illustrated in FIG. 20 at the discharge end of the condenser or muffler.

Referring now particularly to FIG. 1 of the drawings, it will be observed that the reference character 10 designates a base which may be a metal base carrying upper and lower insulators 11 and 12. It will be understood that the length of the insulators 11 and 12 and their spacing apart depend upon the voltage of the system with which the present invention is employed. Upper and lower line contact clips 13 and 14 are carried by the insulators 11 and 12 at their outer ends for detachably receiving upper and lower terminals 15 and 16 that are mounted on the upper and lower ends of a tubular insulating housing or fuse holder 17 of a circuit interrupter that is indicated, generally, at 18. Associated with the lower terminal 16 is a condenser or mufller 19 in which the present invention is embodied.

As shown in FIGS. 2A-2B a coil tension spring 21 and a fiexible cable or conductor 22 interconnect the upper terminal 15 and a spring and cable fastener 23 which forms a part of a replaceable cartridge, shown generally at 24, which can be constructed as set forth in more detail in Patent No. 2,976,381 above referred to. The replaceable cartridge 24 includes a rod-like terminal 25 which is connected at its upper end to the spring and cable fastener 23 and moves therewith upwardly under the influence of the coil tension spring 21 when it is released. At the lower end of therod-like terminal 25 there is a fusible element 26 which is connected to a terminal fitting 27 that extends radially inwardly from a stationary terminal 28 at the lower end of the cartridge 24. The rodlike terminal 25 moves upwardly through a bore 29 that is formed in a body 30 of arc extinguishing material which may be boric acid or other water containing dielectric material. In parallel with the rod-like terminal 25 and fusible element 26 is a strain element assembly 31. It is connected at its upper end to the spring and cable fastener 23 and extends through an auxiliary bore 32 in the body 30 of arc extinguishing material and is connected at its lower end to a strain element pin 33 that extends radially inwardly from the stationary terminal 28. The lower end of the cartridge 24 is closed by a frangible disc 34 that is held in place by a snap locking spring 35. Connection between the terminal 28 and the lower terminal 16 is provided by contact fingers 36 depending from the latter and engaging the periphery of the former. The lower ends of the contact fingers 36 abut a locking ring 37 threaded on the terminal 28.

As pointed out above, when a circuit interrupter of the type illustrated at 18 and described hereinbefore operates to interrupt the flow of fault current, particularly a relatively heavy fault current, a large amount of water vapor is evolved from the the bore 29 in the body 30 of arc extinguishing material. This vapor at extremely high temperature and pressure flows through the bore 29 and out of the lower end of the cartridge 24. The frangible disc 34 initially is promptly expelled along with the vapors comprising gas and metallic products incident to the blowing of the fusible element 26 and release of the strain element assembly 31 which permit the spring 21 to retract the rod-like terminal 25 into the bore 29. When these are products are permitted to flow directly to the atmosphere, no particular problem is involved although care must be taken that the part of the highly ionized are core that usually extends below the discharge end of the fuse cartridge 24 does not cause an external fault to another circuit or to the ground or that the incident shock wave is not too'severe in enclosed installations. When the circuit interrupter 18 is mounted within a relatively small enclosure, provision is made, according to this invention, by mounting the condenser 19 on the lower terminal 16 for confining the arc and for limiting the discharge of are products during the relatively short critical period when the high temperatures and pressures tend to be created with the result that the shock waves incident thereto are reduced to such an extent that an ordinary enclosure can withstand them.

The condenser or muffler 19 includes an adapter 38, which may be formed of brass, having an internal thread 39 for cooperation with an external thread on the lower terminal 16. The adapter 38 has an external thread 40 to receive the upper end of an elongated cylindrical shell 41. The adapter 38 also has a conical surface 42 for engaging the contact fingers 36 and clamping them against the terminal 28.

FIGS. 3, 4, 5 and 6 show more clearly the details of construction of the elongated condenser 19 specially designed and proportioned for use with a fuse type circuit interrupter 18 having a continuous current rating of 200 amperes, a voltage rating of 15,000 volts and an interrupting rating at this voltage of 14,000 amperes. Here it will be observed that the adapter 38 is threaded into the upper end of an elongated cylindrical shell 41 which may be formed of copper alloy tubing or of seamless steel tubing having a wall thickness of 0.'l25" and an internal diameter of 2.500". For this particular application the shell 41 has a length of 6.875". It will be noted that the adapter 38 has a central depending flange 44 the outer surface of which is conical in shape and has a base diameter indicated at 45 of 1.687". At its lower end the shell 41 is slot-ted, as indicated at 46, for receiving a transversely extending bar to facilitate the application or removal of the condenser 19 to or from the terminal 16 at the lower end of the circuit interrupter 18.

Spaced from the lower end of the shell 41 is an annular shoulder 47 for receiving a cover disc 48 which may be formed of .250" copper alloy or hot rolled steel. The cover disc 48 is held in place by brazing, as indicated 59, although it will be understood that other means can be employed for this purpose.

With a view to venting the cylindrical chamber provided by the elongated cylindrical shell 41 to the atmosphere for a limited extent, at least 4 and preferably 8 or more ports 50 are provided through the cover disc 48. They are located along a circle 51 the diameter of which is 1.875 and its center is located along the longitudinal axis of the shell 41. It will be observed that eight equally spaced ports 50 are used. They are drilled to have a diameter of .199" thereby providing a total discharge area of about .250 square inch. The ports 50 are located a distance from the center of the cover disc 48 equal to more than one half its radius.

The are products are discharged from the cartridge 24 through the adapter 38 into the upper end of the elongated cylindrical shell 41. It is desirable that these are products not be permitted to flow directly through the ports 50 to the atmosphere. Also, it is desirable that they be cooled and condensed while they are passing through the shell 41 in order to remove a substantial amount of energy therefrom. For this purpose, in accordance with this invention, a relatively short section 54 of high heat conductivity, relatively rigid, convolutely wound 5 mesh wire screen is provided near the upper end of the shell 41. The wire screen is preferably formed by lengthwise extending wires 55 and circularly extending wires 56 of copper, both 5 to the inch, having a diameter of .063". In the particular embodiment shown, the short section 54 has a length of 1.750" and comprises three and one-half convolutions of the wire screen providing a large opening 57 having a diameter of 1.687" for initially receiving the are core loop and the arc products. This diameter is the same as the diameter 45 at the base of the depending flange 44. Thus the inner periphery of the short section 54 provides the large diameter cylindrical opening or passageway 57 therethrough while the outer periphery of the short section 54 bears against the inner surface of the upper end of the shell 41. The weight of the short section 54 of copper wire screen is about 7 ounces.

In order to remove additional energy from the are products, a long section 60 of high heat conductivity, relatively rigid, convolutely wound wire screen is located at the other or lower end of the shell 41 endwise of the short section 54. Like the short section 54 it is formed by interlaced lengthwise extending wires 61 and circularly extending wires 62 of the same size, material and spacing as the wires 55 and 56. The long sect on 60 is formed by seven convolutions of the copper wire screen and has a length of 4.125" and a weight of 24 ounces. The long section 60 is wound to provide a centrally located small diameter opening or passageway 63 therethrough coaxial with the large diameter opening 57 and having a diameter of .500". The lower end 64 of the opening or passageway 63 is closed by the central portion of the cover disc 48. The outer periphery of the long section 60 of copper wire screen bears against the inner surface of the shell 41.

The interlaced wires 55 and 56 forming the short section 54 of copper wire screen and the interlaced wires 61 and 62 forming the long section 60 of copper wire screen provide a partial filling for the cylindrical chamber formed by the shell 41 that is reticulated lengthwise and transversely with the relatively large diameter opening or passageway 57 for initially receiving the are products and the relatively small diameter opening or passageway 63 in axial alignment therewith for receiving a portion of these are products. Some of the are products in the large diameter opening 57 flow radially outwardly, others flow longitudinally into the upper ends of the convolutions of w re screen forming the long section 60. Because of the reticulated construction the are products are permitted to flow relatively freely not only longitudinally but also transversely of the chamber formed by the shell 41 where they are in contact with the relatively heavy wires forming the sections 54 and 60 which provide a large surface area for extracting heat. Since the wires 5556 and 6162 are relatively rigid and massive, they are better able to withstand without disintegration or collapsing or wadding the intense heat of the are products flowing thereover. This permits reuse of the condenser 19 for many circuit interruptions. However, there is no direct free path through the shell 41 to the ports 50. Instead, the are products, including the water vapor, must flow through the interstices formed by the interlaced wires of the sections 54 and 60 to the ports 50. Since the construction of the sections 54 and 60 and the location of the ports 50 are somewhat critical to provide optimum results for the particular fuse rating mentioned above, the specific materials, dimensions and weights have been identified as above set forth. Thus, it will be observed that the radius of the port circle 51 is about three-fourths the radius of the chamber formed by the shell 41 whereby the ports 50 are positioned closer to the periphery of the disc 48 than to its center. The radius of the cylindrical opening or passageway 57 through the short section 54 is slightly less than the radius of the port circle 51 while the radius of the small diameter opening or passageway 63 is substantially less than the radius of the large diameter opening or passageway 57 so that communication from the chamber in the shell 41 to the atmosphere can take place only through the interstices of the long section 60 and the ports 50.

In some instances it is desirable to interpose one or more discs 67 of high heat conductivity relatively rigid wire screen between the juxtaposed ends of the short and long sections 54 and 60 to hold the ends of the convolutions of wire screen in place and to reduce the degree of direct impingement on the ends of the wires of the long section 60 by the blast of incandescent are products from the cartridge 24. As shown in FIG. 5, the discs 67 are formed of tranversely extending intermeshing wires 68 of the same size, spacing and character as the wires 55 and 56 or 61 and 62 above described. Experience has indicated that, when the discs 67 are employed, for example two discs as shown, the central portions thereof overlying the upper end of the small diameter opening or passageway 63 and directly in line therewith may be fused out by the high temperature are products. Therefore, when the disc or discs 67 are used, they may be provided initially with registering openings equal in diameter to that of the small diameter opening or passageway 63.

When a condenser 19, constructed as described, is provided and the circuit interrupter 18 operates to interrupt the flow of a light or medium fault current, the capacity of the condenser 19 is sufficient to receive the exhaust from the cartridge 24 without appreciable venting to the atmosphere. The vapors and other are products first enter the large diameter opening or passageway 57 and thence flow radially outwardly and longitudinally of the sections 54 and 60 and also into the small diameter opening or passageway 63. They are cooled and condensed as they flow radially and longitudinally and engage the large surface area provided by these sections of copper wire screen. It will be apparent that the reticulated construction of the sections 54 and 60 is such that the are products can penetrate and disperse through a multitude of devious paths which extend in all directions.

When the circuit interrupter 18 operates to interrupt high currents, within its rating, the functioning of the condenser 19 is similar to that described above except that the cooled are products are escaping to a greater extent through the ports 50 in the cover disc 48. Because of this escape, the pressure within the shell 41 is limited and the discharge from the bore 29 in the cartridge 24 is relatively free. This facilitates arc extinction and reduces arcing time and are energy that must be dissipated. The amount of heat absorbed by the condenser 19 and thereby its temperature rise are increased but only to a tolerable extent. Since there is substantially no direct path to the ports 50 by-passing the sections 54 and 60, there is no violent exhaust blast. All are products escaping from the condenser 19 through the ports 50 are substantially cooled before they reach the atmosphere. As a result there is no severe concentrated shock wave particularly when the several ports 50 are located on the relatively large diameter port circle 51 to break up the exhaust into a number of separate jets for dispersal and further as a result of the flow of the are products through the interstices between the wires 61 and 62 forming the long section 60.

Tests have shown that the circuit interrupter 18, equipped with the condenser 19 constructed as described, can withstand full rated voltage of 15,000 volts following interruption of rated short circuit current of 14,000 amperes. This is due to the fact that the venting through the ports 50 is suflicient to prevent excessive temperatures and pressures during the arc interrupting process or subsequent high temperatures within the shell 41 and within the bore 29 of the cartridge 24 or within the insulating housing or fuse holder 17 as the result of heat dissipation from the condenser 19 to the degree that it occurs when a non-vented construction, operating at the same voltage and current, was tested.

The are core that is developed on blowing of the fusible element 26 and strain element assembly 31 is in the form of a loop from the lower edge of the terminal 28 and the retreating lower end of the rod-like terminal 25. This loop extends below the terminal 28 into the condenser 19. By providing the large diameter opening or chamber 57 in the short section 54 of copper wire screen, this are loop is readily accommodated together with the are products without undue restriction and resultant excessive fusion and vaporization of the wires forming this screen section. The arrangement described also allows part of the vapors from the arcing zone to disperse and enter longitudinally and transversely the long section 60 of copper wire screen from its upper end.

It is of interest to disclose certain specific details of construction of the condenser 19 when it is to be used with a fuse type circuit interrupter 18 having a continuous current rating of 400 amperes, a voltage rating of 15,000 volts and an interrupting rating of 22,500 amperes. The shell 41 has a wall thickness of .156", an internal diameter of 3.187" and a length of 8". The diameter of the adapter 38 at 45 is 2.125. The cover disc 48 has a thickness of .250" and a diameter of 3.246. The ports 50 are on port circle 51 having a diameter of 2.500" and are formed by a .3 16 drill to provide a total discharge area of .63 square inch. At least four and preferably eight or more ports 50 providing this total discharge area are used. The short section 54 has an external diameter of 3.187", an internal diameter of 2.125" and a length of 2.1 87" and is formed of 5 mesh copper wire screen with the wires having a diameter of .063". The long section 60 has an external diameter of 3.187", an internal diameter of .500" and a length of 4.750" and is formed of 5 mesh copper wire screen having crossed wires of .063" diameter. The discs 67, if used, having a diameter of 3.187".

FIGS. 7, 8 and 9 of the drawings show a modified construction for the condenser or muffler 19. The short section 54 of convolutely wound copper wire screen is used as before, the discs 67 are omitted, and the convolutions of the long section 60 of convolutely wound copper Wire screen in part abut the convolutions of the short section 54. At its lower end the long section 60 is spaced from the cover disc 48 by a cylindrical spacer 69 to provide a space 70 communicating with the ports 50. A filler plug 71 extends into the lower end of the central small diameter opening 63 and it is held in place by a screw 72 extending through the cover disc 48. Like the construction previously described and for the reasons there set forth, there is no direct path to the ports 50 from the lower discharge end of the fuse cartridge 24. The are products are required to flow through the interstices of the reticulated filling provided by the short section 54 and long section 60 of copper wire screen and finally longitudinally of the latter into the annular space 70 around the filler plug 71 whence they are vented to the atmosphere through the ports 50.

In FIGS. 10, 1'1 and 12 a modified construction for the condenser or muffler 19 is shown for use in conjunction with the circuit interrupter 18. Spaced from the lower end of the shell 41 is the annular shoulder 47 that is arranged to receive thereagain-st a marginal portion of a cover disc or closure 73 which is held in place by the inturned lower marginal edge 49' of the shell 41. The cover disc or closure 73 is vented by a number of large 9 diameter ports 74. As shown in FIG. 11 the ports 74 may be four in number and may have a diameter of the order of Centrally of the cover disc or closure 73 is a threaded opening 75 the purpose of which will be apparent presently.

With a View to cooling and condensing the are products incident to the blowing of the fusible element 26 the short section 54 of convolutely wound heavy gauge wire screen is provided in the upper end of the shell 41 and is centered by the depending flange 44. It is formed by lengthwise extending wires 55 woven with circularly extending wires 56 and then is convolutely wound on a suitable mandrel to provide the relatively large diameter opening at 57 coaxial with the longitudinal axis of the shell 41 and of the bore 29. In addition, there is provided therebelow the relatively long section 60 of convolutely wound heavy gauge wire screen which is formed by lengthwise extending wires 61 woven with circularly extending wires 62.

The long section 60 of convolutely wound reticulated wire mesh is formed to provide the longitudinally extending small diameter opening 63 therethrough. Positioned in this small diameter opening 63 is a tubular member or hollow stem 76 which is formed of metal, such as copper, and is threaded at its lower end 77 for insertion in the threaded opening 75 in the cover disc or closure 73. In this manner the tubular member or hollow stem 76 is held by the elongated cylindrical shell 41 and extends upwardly centrally therethrough with the long section 60 of wire screen surrounding it.

It will be observed that the threads 77 at the lower end of the tubular member or hollow stem 76 extend upwardly a substantial distance. The purpose of this is to receive a correspondingly threaded opening 78 in a disc or closure member 79 that is slightly smaller in external diameter than the cover disc 48. Its diameter is such that it can be inserted freely into the lower end of the elongated cylindrical shell 41. As shown in FIG. 11 the cover member or disc 79 is provided with relatively small diameter openings or ports 80. For example, they may be four in number and may have a diameter of /4" while, as pointed out, the cover disc 73 may have four relatively large diameter ports 74. The position of the disc 79 with respect to the cover disc 48 is such that the ports 80 therein are out of alignment with the ports 74. The reason for this arrangement is to provide an indirect rather than a direct path for the flow of the are products from the relatively small openings or ports 80 in the disc 79 at the lower end of the long section 60 of wire mesh to the atmosphere. The exhaust jets from the ports 80 impinge on the upper side of the cover disc 73 and are deflected laterally to reduce the velocity of the exhaust products before they reach the atmosphere through the relatively large ports 74 in the cover disc 73 thereby reducing the reach of the jets of arc products exhausted to the outside.

It will be observed in FIG. that the disc 79 is spaced upwardly from the cover disc 73 to provide an annular space or exit exhaust chamber 81 therebetween and around the threaded lower end 77 of the tubular member or hollow steam 76. The space 81 can 'be a free space, as shown here, or it can be filled with additional condensing material as shown in FIG. 14 and described hereinafter. The central opening through the tubular member of hollow stem 76 is indicated at 82 in FIGS. 10 and 12 of the drawings. It will be noted that this opening 82 extends upwardly through the tubular member or hollow stem 76 and is in direct alignment with the bore 29 in the body of arc extinguishing material 30. Its lower end is closed and radial openings 83 are formed which place the openings 82 in restricted communication with the space surrounding the tubular member or hollow stem 76 and occupied by the long section 60 of wire mesh at points remote from its lower end. This arrangement permits the flow of the part of the are products which 10 enter the upper end of the opening 82 into the surrounding interstices of the long section 60 of Wire mesh. However, there is no direct path from the arcing zone of the circuit interrupter 18 through the small diameter opening '63 in the long section 60 of wire mesh to the portion thereof adjacent the ports in the disc 79.

At the upper end of the tubular member or hollow stem 76 there is mounted a barrier or deflecting member or shield which is indicated at 84. The barrier member 84 may be formed integrally with the tubular member or hollow stem 76 and thus formed of the same material. Alternatively, it can be formed separately and, as shown, threaded on the upper end of the tubular member of hollow stem 76. Instead of being formed of metal, the barrier member 84 can be formed, in part, of arc resisting material such as a ceramic material as described hereinafter. When the barrier member 84 is employed as an arc terminal, it can be formed of arc resisting material such as silver tungsten or tungsten carbide. In any case the barrier member 84 is apertured with the opening 82 through the tubular member or hollow stem 76 extending through it so that the flow of part of the are products therethrough aids in maintaining the arc root in the central region. It has a conical deflecting surface 85 which serves to direct a portion of the arc blast into the surrounding short section 54 of wire mesh. Some of the blast flows directly into the upper end of the exposed portion of the long section '60 of wire mesh while a limited amount flows into the upper end of the opening 82 through the barrier member 84 and tubular member or hollow stem 76 and thence through the radial openings 83 into the surrounding interstices of the long section 60 of wire mesh.

In operation, with reference to FIGS. 10, 11, 12 and 13, on blowing of the fusible element 26 followed by release of the strain element assembly 31, an arc is drawn between the terminal fitting 27 and the retreating end of the rod-like terminal 25 in the bore 29 in the body of arc extinguishing material 30. An arc extinguishing gas is evolved and it, together with the ionized are products and metal vapor, is a part of a mixture that flows with a blast action through the stationary terminal 28. The frangible disc 34 is ruptured, the blast extends into the large diameter opening 57, and it, together with the arc, impinged on the barrier member 84 which, if [formed of metal, may provide a location to which the arc root may transfer. The barrier member 84 prevents direct impingement of the are products on the more finely divided material making up the long section 60 of wire mesh which, without the barrier member 84, would be more directly in the path of the discharge from the bore 29. Rather, it deflects the flow of the are products and disperses them into short section 54 and the peripheral entrance to long section 60. At the same time a limited portion of the are products flows through the opening 82 and is discharged radially through the openings 83 into the surrounding long section 60 of wire mesh. When the barrier member 84 is formed of ceramic material or is formed of metal overlaid by ceramic material, it serves principally as a defleeting member since the ceramic material, because of its insulating properties, does not lend itself to the establishment of an arc root therefrom. Although such a construction shields the screen material from direct impingement of the blast from the bore 29, the possibility of direct attack by the deflected arc is greater. This can be overcome by using the modified construction shown in FIG. 13 and described hereinafter. The arc products are cooled and condensed as they disperse and flow into and through the interstices of the short section 54 and long section 60 of wire mesh. By the time that they flow through the ports '80 in the disc 79 their temperature and pressure are reduced substantially. The annular space 81 provides a further cooling and condensing action and, since the ports 74in the cover disc 73 are staggered with respect to the ports 80, there is lateral diffusion of the arc 11 products and reduction in their velocity before ports 74 exhaust the are products to the atmosphere through their larger area.

FIG. 13 shows at 84' the modified construction for the barrier member or shield above referred to. Here it will be observed that a metallic adapter 86 is threaded onto the upper end of the tubular member or hollow stem 76. Threaded or otherwise secured .to the metallic adapter 86 is a barrier member or shield 87 in the form of an annular disc of ceramic material having a conical deflecting surface 88 which, like the surface 85, serves to redirect the arc products outwardly. The arc, shown schematically at 89, has one are root located at 90 on the exposed surface of the metallic adapter 74 and there is a tendency for it to be located in this vicinity since a portion of the arc products flows through the opening 82 in the stem 76.

In FIGS. 14 and 15 another embodiment of the elongated condenser or muffler 19 is shown. It will be observed that the opening 89 through the tubular member or hollow stem 76 extends entirely there-through and that a suitable closure 91 is provided at the lower end against which a coiled compression spring 92 reacts. The closure 91 can be secured in place in any suitable manner in the lower end of the tubular member or hollow stem 76 and, if desired, it can be an integral construction. The coil compression spring 92 reacts upwardly against the lower end of the inner stem 93 which is slidably mounted in the opening 82 through the tubular member or hollow stem 76. At its upper end the inner stem 93 carries a barrier or deflecting member or shield 94 that is formed of the materials above described for the barrier member 84. The barrier member 94 has a similar conical deflecting surface 95 and the construction is such that the longitudinal opening 96, FIG. 15, extends downwardly through the barrier member 94 and entirely through the inner stem 93. In addition to the longitudinal opening 96, radial openings 97 are provided in the side walls of the inner stem 93 and they are arranged to register with the radial openings 83 in the tubular member or hollow stem 76 when the barrier member 94 and the inner stem 93 on which it is mounted are moved downwardly to compress the spring 92 as a result of the endwise pressure applied thereto by the blast which results from the blowing of the fusible element 26 and the flow downwardly through the opening in the stationary terminal 28 of the arc products.

It will be understood that the coil compression spring 92 holds the barrier member 94 in close proximity to the lower discharge end of the replaceable cartridge 24 or in contact therewith. In some respects the barrier member 94 and the inner stem 93 on which it is mounted act like a spring operated valve in the movement downwardly under the force incident to the blowing of the circuit interrupter 1 8. The downward movement is limited by the engagement of the undersurface of the barrier member 94 with the upper end of the tubular member or hollow stem 76. Any suitable means can be employed for guiding the inner stem 93 in the tubular member or hollow stem 76 to prevent relative rotationto the end that, when the barrier member 94 is in its lowermost position, the longitudinal opening 96 will be in register with certain of the radial openings 83 while the radial openings 97 in the inner stem 93 register with the other radial openings 83.

In the embodiment of the invention shown in FIG. 14 advantage is taken of the annular space 81 to provide therein cooling and condensing means in the form of plates 98. The plates 98 may be formed of any suitable metal, such as copper, and they are provided with punched apertures 99 that are formed as to provide depending slivers 100 which serve to space the plates 98 apart and from the cover disc 73. It will be understood that the plates 98 are so positioned between the disc 79 and the cover disc 73 that the openings 99 are not in direct alignment thereby providing an additional indirect path for the flow and lateral dispersal of the are products before they reach the discharge ports 74 in the cover disc 73.

The operation of the elongated condenser or mufl'ler 19 constructed as shown in FIGS. 14 and 15 is similar to the operation described above for the condenser or mufiler 19 shown in FIG. 10. Further improvement in control of the blast issuing from the bore 29 and in reduction of the external blast action is effected through the provision of the movable barrier member 94 and by the use of the plates 98 with the slivers formed therefrom and providing additional cooling and condensing action in the annular space 81.

A further modified construction is shown in FIG. 16. Here it will be observed that the disc 79, instead of being provided with four A diameter ports 80, is provided with a larger number of smaller diameter ports or apertures 101. They also act as a restriction to the free flow of the arc products from the lower end of the long section 60 of wire mesh into the annular space 81 while providing for greater initial dispersal of the are products that enter it.

A different arrangement may be provided for the cover disc 73. Here either the large diameter ports 74, previously described, can be used or a larger number of smaller diameter apertures or ports 102 of relatively large total area can be provided and located out of alignment with the apertures or ports 101 in the disc 79. By using a relatively small number of relatively large openings 102 in the cover disc 73 the velocity of the flow of the are products therethrough is reduced and there is at corresponding reduction in the reach of the exhaust jets at the lower end of the condenser or mufller 19 to the atmosphere.

FIGS. 17 and 18 show the details of construction of another embodiment of the condenser or mufller 19 in which the present invention is embodied. Here it will be observed that the adapter 38 is threaded into the upper end of the shell 41 which may be formed of copper alloy tubing or of seamless steel tubing having a wall thickness suflicient to withstand the pressure to which it is likely to be subjected within its current interrupting rating.

The adapter 38 has a central depending flange 44 the outer surface of which is conical in shape. At its lower end the shell 41 is transversely slotted, as indicated at 46, for receiving a transversely extending bar to facilitate the application to or the removal of the condenser or mufiier 19 from the terminal 16 at the lower end of the circuit interrupter 18.

Spaced from the lower end of the shell 41 is the annular shoulder 47 that is arranged to receive thereagainst the margin-a1 portion of the cover disc or closure 48 which is held in place by the inturned lower marginal edge 49 of the shell 41. The cover disc or closure 48 is vented by a number of exhaust ports 50.

With a view to cooling and condensing the are products incident to the blowing of the fusible element 26 and strain element assembly 31 the short section 54 of convolutely wound heavy gauge wire screen is provided in the upper end of the shell 41 and is centered by the depending flange 44. It is formed by lengthwise extending wires 55 woven with circularly extending wires 56 and then is convolutely wound on a suit-able mandrel to provide the relatively large diameter opening or passageway at 57 coaxial with the longitudinal axis of the shell 41 and of the bore 29. The outer surface 58 of the short section 54 of wire screen is in close juxtaposition to the inner surface of the chamber provided by the shell 41 while the inner surface 59 of the short section 54 of wire screen is positioned out of the direct path of the discharge through the throat 44 of the central flange 44.

Below the short section 54 of wire screen there is positioned the relatively long section 60 of convolutely wound heavy gauge wire screen which is formed by lengthwise extending wires 61 woven with circular extending wires 62 and has the small diameter opening 63 therethrough the lower end 64 of which is closed by the cover disc or closure 48. The outer surface 65 of the 13 long section 60 of wire screen is positioned in close juxtaposition to the inner surface of the chamber provided by the shell 41. The inner surface of the opening 63 is indicted at 66.

The long section 60 of wire screen is positioned around the body of an imperforate metallic stud 103 that may be formed of a material of good heat conductivity and high heat capacity such as a copper alloy. The body is threaded as indicated at 104 for the purpose of securing the stud 103 in place in the opening 63 which has a substantially smaller diameter than the diameter of the opening or passageway 57 through the short section 54 of wire screen. The lower end of the stud is beveled to facilitate entry into the opening 63 and the outer surface 65 of the long section 60 is forced into intimate contact with the inner surface provided by the shell 41 as the stud is screwed into place. At its upper end the stud 103 has an integral head 105 the underside of which overlies and bears against the inner convolutions of the long section 60 of wire screen.

It will be observed that the head 105 is located in alignment with the throat 44 through which the arc products flow from the bore 29 of the circuit interrupter 18 on blowing of the fusible element 26 and strain element assembly 31. In this position the head 105 receives directly the full effects of the heat and pressure incident to the flowing of the are products through the throat 44. Because of its relatively massive size and heat capacity, it is capable of withstanding several circuit interruptions, although each time it is eroded to a certain extent.

Since the head 105 is located in the position described the are products are caused to flow laterally after impingement on it. The flow into the interstices of the surrounding short section 54 of wire screen and also downwardly endwise through the interstices of the long section 60 of wire screen. Finally they are discharged through the exhaust ports 50 to the atmosphere. However, there is no direct path to the exhaust ports 50. Rather the products of the arc are required to flow through t-hhe interstices in the short section 54 of wire screen and the long section 60 of wire screen where they are expanded, cooled and condensed.

' Preferably the short section 54 and long section 60 of wire screen are formed of copper wires of such size that they are relatively self supporting and are not likely to be crushed by the pressure that they may be subjected to within the limits of the rated interrupting capacity of the interrupter 1-8. For illustrative purposes as pointed out hereinbefore the sections 54 and 60 can be formed of mesh copper wire screen, the wire having a diameter of .063". Somewhat larger or smaller diameter wires can be employed for the sections 54 and 60. Preferably they should be chosen so that a self supporting structure is provided that will not be crushed or deformed when subjected to the pressure incident to the normal expected operation.

FIG. 19 shows another construction for the condenser or muffler 19. Here a single exhaust port 106 is provided in the cover disc or closure 48 in alignment with and having substantially the same diameter as the opening 63 through the long section 60 of convolutely wound wire screen. The gaseous are products then are caused to flow through the interstices of the sections 54 and 60 into the opening 63 and thence to the atmosphere through the exhaust port 106. Since this is a somewhat more direct path to the atmosphere than is provided when the construction shown in FIG. 17 is employed, it is desirable to provide for deflecting laterally the blast that flows through the exhaust port 106. For this purpose a deflecting member 107 is employed. It may be formed of good conducting material such as brass with a shank 108 that is secured by a bolt 109 to the underside of the cover disc or closure 48. The deflecting member 107 has a bottom wall 110 that underlies the exhaust 14 port 106 and extends somewhat beyond it. Side Walls, one of which is shown at 111, serve to confine the blast and to direct it laterally.

At the upper end of the opening 63 through the long section 60 of wire screen there is positioned an imperiorate metallic stud 112 that may be formed of brass. It is provided with a knurled or burred surface 113 to hold it in place along the inner surface 66 of the long section 60 of wire screen. At its upper end the stud 112 has an integral head 114 that corresponds to the head for the stud 103. With a view to centering one are root that may transfer to and extend from the stud 112 a cavity 115 is formed in the head 114. In addition the head 114 is provided with an annular arc resisting member 116, preferably formed of ceramic material, along its upper and outer edge for the purpose of resisting erosion as result of repeated circuit interruption using the same condenser or mufller 19. It will be understood that the stud 112 can be interchanged with the stud 103, if desired.

A further modification is illustrated in FIGS. 20 and 21 of the drawings. Here it will be observed that the cover disc or closure 48 is provided with exhaust ports 117 that are four in number and may have a diameter of the order of /2. A tapped hole 118 is provided in the cover disc or closure 48 for receiving a threaded end 119 of an imperforate metallic stud 120 that extends entirely through the opening 63 in the long section 60 of wire screen. At its upper end the stud 120, which preferably is formed of good conducting material such as brass, has an integral hexagonal head 121 the purpose of which is the same as the head 105 previously described for directing the flow of the arc products into the interstices of the sections 54 and 60 of wire screen.

In the construction here shown the section 60 of wire screen does not extend entirely to the cover disc or closure 48. Rather the long section 60 extends to an inner closure plate 122 that is provided with a tapped hole 123 for receiving the threaded end 119 of the stud 120. Thereby the inner closure plate 122 is held in position spaced inwardly from the cover disc or closure 48. The inner closure plate 122 is provided with exhaust ports 124 that may be four in number and having a diameter of As seen in FIG. 21 the exhaust ports 124 are located out of alignment with the exhaust ports 117 in the cover disc or closure 48. Between the closure plates 48 and 122 an exhaust chamber 125 is formed into which the cooled and condensed products flow from the exhaust ports 124. They expand somewhat in the exhaust chamber 125 and flow to the atmosphere through the exhaust ports 117.

FIG. 22 shows a further modification of the construction in FIG. 17. The long section :60 of convolutely wound wire screen extends fully to the cover disc 48 which is located at the lower end of the elongated cylindrical shell 41 where it is held in place by the inturned end 49 against shoulder 47. The long section 60 of wire screen extends around an imperforate stud 126 the upper end portion of which isgprovided with a hexagonal head, such as the head 121, FIG. 20, which is located in the large diameter opening 57 in the short section '54 of convolutely wound wire screen which initially receives the are products. The imperforate stud 26 has a reduced diameter lower end 127 that extends through a central opening 128 in the cover disc 48. The extreme lower end of the reduced diameter end 1 27 is formed over to hold the imperforate stud 126 securely in position on the cover disc 48. A beveled surface 129 is formed on the lower end of the reduced diameter end 127 and a beveled shoulder 130 is formed at the upper end to facilitate entry of the imperforate stud 126 into the opening 63 in the long section 60 of wire screen the outer surface of which is thereby forced snugly into engagement with the inner surface of the elongated cylindrical shell 41. This insures that there is no free passageway therebetween along which there could be unobstructed flow of the arc products to the ports 50.

What is claimed as new is:

1. In a circuit interrupter, in combination, means for establishing an arc in an arcing passageway directly communicating with a discharge passageway of larger cross sectional area for unrestricted flow therefrom of condens able gas at high temperature and pressure, an elongated cylindrical shell joined to said arc establishing means and providing a cylindrical chamber for receiving said gas at one end, a closure at the other end of said chamber, a first annular section of high heat conductivity relatively rigid wire screen at said one end of said chamber with its outer periphery engaging the inner surface thereof and substantially filling the same, said first annular section being reticulated lengthwise and transversely of said chamber and its inner periphery defining a relatively large passageway the cross sectional area of which is greater than the cross sectional area of said discharge passageway, a second annular section of high heat conductivity relatively rigid wire screen end-wise of said first section and at said other end of said chamber with its outer periphery engaging the inner surface thereof and substantially filling the same, said second annular section being reticulated lengthwise and transversely of said chamber and its inner periphery defining a relatively small passageway as compared to said passageway in said first section, a filler plug extending from said closure into the adjacent end of said small passageway, means spacing said second annular section from said closure whereby an annular space is provided therebetween around said filler plug, and means porting said annular space to the atmosphere.

2. In a circuit interrupter, in combination, means for establishing an arc at one end of a bore extending through solid arc extinguishing material from which a flow of condensable gas is evolved at high temperature and pressure due to the heat of the arc through a discharge passageway having substantially unrestricted flow therethrough, an elongated cylindrical shell joined to said arc establishing means and providing a cylindrical chamber for receiving said gas at one end axially endwise thereof from said discharge passageway, closure means at the other end of said chamber, first cooling and condensing means at said one end of and substantially filling said shell providing a relatively large cross section area opening axially endwise therethrough and of said bore for receiving the initial portion of the arc blast and are products including said condensable gas, the area of said opening being greater than the cross sectional area of said discharge passageway, and second cooling and condensmg means endwise of said first cooling and condensrng means in and substantially filling said chamber reticulated lengthwise and transversely thereof and providing a relatively small cross section area opening axially endwise therethrough and coaxial with said relatively large cross section area opening, said closure means being provided with a plurality of ports therethrough to the atmosphere located along a circle coaxial with and having a diameter greater than therrnaximum transverse dimension of said small cross section area opening whereby communication from said chamber to the atmosphere can take place through said ports only through the interstices of said second cooling and condensing means.

3. In a circuit interrupter, in combination, means for establishing an arc in an arcing passageway directly communicating with a discharge passageway of larger cross sectional area for unrestricted flow therefrom of condensable gas at high temperature and pressure, an elongated cylindrical shell joined to said are establishing means and providing a cylindrical chamber for receiving said gas at one end and centrally thereof, a closure at the other end of said chamber secured to said shell against detachment under those conditions in said chamber of temperature and pressure likely to be developed within the rated capacity of the circuit interrupter, and annular wire screen means substantially filling the major portion of said cylindrical chamber, said annular wire screen means being reticulated lengthwise and transversely of said chamber with the inner surface defining a cylindrical passageway therethrough along the longitudinal axis having one end closed by said closure, the end of said passageway adjacent said one end of said cylindrical shell having a relatively large cross sectional area for a substantial portion of the length thereof as compared to the cross sectional area of the remaining portion thereof and greater than the cross sectional area of said discharge passageway to receive the initial arc blast with a minimum of interference with the flow of arc products incident thereto, said closure having a plurality of ports extending therethrough and out of alignment with said passageway and permitting communication to the atmosphere from said chamber only through said Wire screen means.

4. In a circuit interrupter, in combination, means for establishing an arc in an arcing passageway directly communicating with a discharge passageway of larger cross sectional area for unrestricted flow therefrom of condensable gas at high temperature and pressure, an elongated cylindrical shell joined to said are establishing means and providing a cylindrical chamber for receiving said gas at one end and centrally thereof, a closure at the other end of said chamber secured to said shell against detachment under those conditions in said chamber of temperature and pressure likely to be developed within the rated capacity of the circuit interrupter, annular wire screen means substantially filling the major portion of said cylindrical chamber, said annular wire screen means being reticulated lengthwise and transversely of said chamber with the inner surface defining a cylindrical passageway therethrough along the longitudinal axis having one end closed by said closure, the other end of said cylindrical passageway having a cross sectional area greater than the cross sectional area of said discharge passageway for receiving freely said flow of condensable gas, said closure having a plurality of ports extending therethrough and out of alignment with said passageway and permiting communication to the atmoshpere from said chamber only through said wire screen means, and a filler plug extending from said closure for a substantial distance into said one end of said passageway.

5. In a circuit interrupter, in combination, means for establishing an arc in an arcing passageway directly communicating with a discharge passageway of larger cross sectional area for unrestricted flow therefrom of condensable gas at high temperature and pressure, an elongated cylindrical shell joined to said arc establishing means and providing a cylindrical chamber for receiving said gas at one end, closure means closing off the other end of said chamber and provided with port means to the atmosphere, at first convolutely wound section of high heat conductivity relatively rigid wire screen at said one end of and substantially filling said chamber with its inner periphery defining an opening having an area greater than the cross sectional area of said discharge passageway, and a second convolutely wound section of high heat conductivity relatively rigid wire screen endwise of and substantially filling said first section and at said other end of said chamber with its inner periphery defining an opening closed at its outer end by said closure means and having an area substantially less than said area of said opening in said first section whereby communication from said chamber to the atmosphere through said port means can take place only through the interstices of said second section.

6. In a circuit interrupter, in combination, means for establishing an arc at one end of a bore extending through solid arc extinguishing material from which a flow of condensable gas is evolved at high temperature and pressure due to the heat of the are through a discharge passageway having substantially unrestricted flow therethrough, an elongated cylindrical shell joined to said are establishing means and providing a cylindrical chamber for receiving said gas at one end axially endwise thereof from said discharge passageway, closure means at the other end of said chamber, first cooling and condensing means at said one end of and substantially filling said shell providing a relatively large cross section area opening axially endwise therethrough and of said bore for receiving the initial .portion of the arc blast and are products including said condensable gas, the area of said opening being greater than the cross section-a1 are-a of said discharge passageway, and second cooling and condensing means endwise of said first cooling and condensing means in and substantially filling said chamber providing :a relatively small cross section area opening axially endwise therethrough and coaxial with said relatively large cross section area opening, said closure means being provided with port means therethrough to the atmosphere so located that communication from said chamber to the atmosphere can take place through said port means only through the interstices of said second cooling and condensing means.

7. In a circuit interrupter, in combination, means for establishing an arc in an arcing passageway directly communicating with a discharge passageway of larger cross sectional area for unrestricted flow therefrom of coudensable gas at high temperature and pressure, an elongated cylindrical shell joined to said are establishing means and providing a cylindrical chamber for receiving said gas at one end and centrally thereof, a closure at the other end of said'chamber secured to said shell against detachment under those conditions in said chamber of temperature and pressure likely to be developed within the rated capacity of the circuit interrupter, and annular wire screen means substantially filling the major portion of said cylindrical chamber, said annular wire screen means being reticulated lengthwise and transversely of said chamber with the inner surface defining a cylindrical passageway therethrough along the longitudinal axis having one end closed by said closure, that portion of said cylindrical passageway at said one end of said chamber having an area greater than the area of said discharge passageway, said closure having a plurality of ports extending therethrough and out of alignment with said passageway and permitting communication to the atmosphere from said chamber only through said wire screen means.

8. In a circuit interrupter, in combination, means for establishing an arc in an arcing passageway directly communicating with a discharge passageway of larger cross sectional area for unrestricted flow therefrom of condensable gas at big temperature and pressure, an elongated cylindrical shell joined to said are establishing means and providing a cylindrical chamber for receiving said gas at one end and centrally thereof, a closure at the other end of said chamber secured to said shell against detachment under those conditions in said chamber of temperature and pressure likely to be developed within the rated capacity of the circuit interrupter, and annular wire screen means substantially filling the major portion of said cylindrical chamber, said annular wire screen means being reticulated lengthwise and transversely of said chamber with the inner surface defining an opening therethrough along the longitudinal axis having one end closed by said closure, the end of said opening adjacent said one end of said cylindrical shell having a relatively large cross sectional area for a substantial portion of the length thereof as compared to the cross sectional area of the remaining portion thereof and greater than the cross sectional area of said discharge passageway to receive the initial arc blast with a minimum of interference with the flow of are products incident thereto, said closure having port means extending therethrough and out of alignment with said opening and permitting communication to the atmosphere from said chamber only through said wire screen means.

9. In a circuit interrupter, in combination, means for establishing an arc at one end of a bore extending through solid arc extinguishing material from which a flow of condensable gas is evolved at high temperature and pressure due to the heat of the are drawn between a stationary metallic terminal at said one end of said bore and a rod-like metallic tenminal movable endwise through said bore away from said one end thereof from which terminals metallic vapor is derived and mixed with said gas to form are products flowing out of said one end of said bore, an elongated cylindrical shell joined to said arc establishing means and constituting an endwise extension of said bore at said one end thereof and providing a cylindrical chamber for receiving said are products at one end thereof, a closure at the other end of said chamber secured to said shell against detachment under those conditions of temperature and pressure in said chamber likely to be developed within the rated capacity of the circuit interrupter, a body of condensing means within said cylindrical chamber comprising a lengthwise and transversely reticulated convolutely wound wire screen substantially filling a major portion of said cylindrical chamber and defining a passageway therethrough in alignment with said bore with its outer end juxtaposed to said closure, an apertured stem supported at one end centrally of said shell and extending through said body of condensing means, and barrier means supported on the distal end of said apertured stem in alignment with said bore for deflecting a substantial portion of said arc products into said body of condensing means, said barrier means having a central aperture and a passageway therefrom extending into and communicating with said body of condensing means through said apertured stem.

10. The invention, as set forth in claim 9, wherein the stem is longitudinally apertured, and an inner stem is slidably mounted in the aperture of said stem and is biased endwise thereof and carries the barrier means at its outer end.

11. In a circuit interrupter, in combination, means for establishing an arc and causing a flow of condensable gas at high temperature and pressure, an elongated cylindrical shell joined to said arc establishing means and providing a cylindrical chamber for receiving said gas at one end and centrally thereof, a closure at the other end of said chamber secured to said shell against detachment under those conditions of temperature and pressure likely to be developed within the rated capacity of the circuit interrupter and having exhaust port means venting said chamber to the atmosphere, a first annular section of Wire screen at said one end of said chamber with its outer periphery juxtaposed to the inner surface thereof and substantially filling the same and its inner surface out of the direct path of said gas flow and defining a passageway for receiving the same having a relatively large diameter, an imperforate metallic stud having a relatively small diameter extending along the longitudinal axis of said chamber between said passageway and said closure with one end directly in said path of gas flow for receiving and deflecting the same radially outwardly toward said inner surface of said first annular section of wire screen, and a second annular section of wire screen surrounding said stud and interposed between said first annular section of wire screen and said closure with its outer periphery juxtaposed to said inner surface of said chamber and substantially filling the same for receiving through its interstices said deflected gas flow to cool and condense the same before exhaustion to the atmosphere through said exhaust port means, said first and second annular sections of wire screen being reticulated lengthwise and transversely and being sufiiciently rigid to be self supporting and capable of resisting without crushing the pressure incident to said gas flow likely 19 to be developed within the rated capacity of the circuit interrupter.

12. The invention, as set forth in claim 11, wherein the studhas a gas deflecting head extending radially from the body thereof, and said head is disposed in juxtaposed overlying relation to the adjacent portion of the second annular section of wire screen.

13. The invention, as set forth in claim 11, wherein the other end of the stud is spaced from the closure, and the exhaust port means comprises a plurality of openings extending through said closure and out of alignment with said stud.

14. The invention, as set forth in claim 11, wherein the stud extends through the second annular section of wire screen and its other end is secured to the closure, and the exhaust port means comprises a plurality of openings extending through said closure and out of alignment with said stud.

15. In a circuit interrupter, in combination, means for establishing an are at one end of a bore extending through solid arc extinguishing material from which a flow of condensable gas-is evolved at high temperature and pressure due to the heat of the are through a discharge passageway having substantially unrestricted fiow therethrough, an elongated cylindrical shell joined to said are establishing means and providing a cylindrical chamber for receiving said gas at one end axially endwise thereof from said discharge passageway, first apertured closure means at the other end of said chamber, first cooling and condensing means at said one end of said shell and substantially filling the same providing a relatively large cross section area opening axially endwise of said passageway for receiving the initial portion of the arc blast and are products including said condensable gas, the area of said opening being greater than the cross sectional area of said discharge passageway, second cooling and condensing means endwise of said first cooling and condensing means in said chamber and substantially filling the same, second apertured closure means in said chamber juxtaposed to said second cooling and condensing means and spaced inwardly from said first closure means and providing an exhaust chamber therebetween, third cooling and condensing means in said exhaust chamber, the apertures in said second closure means being relatively small in total area to restrict the flow of gas therethrough and the apertures in said first closure means being relatively large in total area to reduce the velocity and reach of the gas flow therethrough, stud means extending along the'longitudinal axis of said shell from said relatively large cross section area opening in said first cooling and condensing means into said second cooling'and condensing means, and barrier means supported on said stud means in said relatively large cross section area opening in said first cooling and condensing means in alignment with said bore for deflecting a substantial portion of said are products into said second cooling and condensing means.

References Cited by the Examiner UNITED STATES PATENTS 1,596,234 8/1926 Bogle 200- 2,091,423 8/1937 Triplett 200-417 2,319,277 5/1943 Triplett 200-117 3,178,537 4/1965 Patterson 200l20 BERNARD A. GILHEANY, Primary Examiner.

H. B. GILSON, Assistant Examiner. 

1. IN A CIRCUIT INTERRUPTER, IN COMBINATION, MEANS FOR ESTABLISHING AN ARC IN AN ARCING PASSAGEWAY DIRECTLY COMMUNICATING WITH A DISCHARGE PASSAGEWAY OF LARGER CROSS SECTIONAL AREA FOR UNRESTRICTED FLOW THEREFROM OF CONDENSABLE GAS AT HIGH TEMPERATURE AND PRESSURE, AN ELONGATED CYLINDRICAL SHELL JOINED TO SAID ARC ESTABLISHING MEANS AND PROVIDING A CYLINDRICAL CHAMBER FOR RECEIVING SAID GAS AT ONE END, A CLOSURE AT THE OTHER END OF SAID CHAMBER, A FRIST ANNULAR SECTION OF HIGH HEAT CONDUCTIVITY RELATIVELY RIGID WIRE SCREEN AT SAID ONE END OF SAID CHAMBER WITH ITS OUTER PERIPHERY ENGAGING THE INNER SURFACE THEREOF AND SUBSTANTIALLY FILLING THE SAME, SAID FIRST ANNULAR SECTION BEING RETICULATED LENGTHWISE AND TRANSVERSELY OF SAID CHAMBER AND ITS INNER PERIPHERY DEFINING A RELATIVELY LARGE PASSAGEWAY THE CROSS SECTIONAL AREA OF WHICH IS GREATER THAN THE CROSS SECTIONAL AREA OF SAID DISCHARGE PASSAGEWAY, A SECOND ANNULAR SECTION OF HIGH HEAT CONDUCTIVITY RELA- 